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参数资料
| 型号： | ISL43485IB-T |
| 厂商： | INTERSIL CORP |
| 元件分类： | 通用总线功能 |
| 英文描述： | 3.3V, Low Power, 30Mbps, RS-485/RS-422 |
| 中文描述： | LINE TRANSCEIVER, PDSO8 |
| 封装： | PLASTIC, MS-012-AA, SOIC-8 |
| 文件页数： | 8/11页 |
| 文件大小： | 477K |
| 代理商： | ISL43485IB-T |
8
Driver Features
The RS-485, RS-422 driver is a differential output device
that delivers at least 1.5V across a 54
load (RS-485), and
at least 2V across a 100
load (RS-422) even with
V
CC
= 3V. The driver features low propagation delay skew to
maximize bit width, and to minimize EMI, and it is tri-statable
via the active high DE input.
Outputs of the ISL43485 driver are not slew rate limited, so
faster output transition times allow data rates of at least
30Mbps.
Data Rate, Cables, and Terminations
Twisted pair is the cable of choice for RS-485, RS-422
networks. Twisted pair cables tend to pick up noise and
other electromagnetically induced voltages as common
mode signals, which are effectively rejected by the
differential receivers in this IC.
RS-485, RS-422 are intended for network lengths up to
4000’, but the maximum system data rate decreases as the
transmission length increases. Devices operating at 30Mbps
are often limited to lengths of less than one hundred feet.
Figure 6 details the ISL43485’s 30Mbps performance driving
200’ of “CAT5” cable terminated in 120
at both ends. Note
that the differential signal delivered to the receiver at the end
of the cable (A-B) still exceeds 1.5V peak. Longer cable
lengths are possible by reducing the data rate, as shown in
Figure 7 for a data rate of 20Mbps.
To minimize reflections, proper termination is imperative
when using this 30Mbps device. In point-to-point, or point-to-
multipoint (single driver on bus) networks, the main cable
should be terminated in its characteristic impedance
(typically 120
) at the end farthest from the driver. In multi-
receiver applications, stubs connecting receivers to the main
cable should be kept as short as possible. Multipoint (multi-
driver) systems require that the main cable be terminated in
its characteristic impedance at both ends. Stubs connecting
a transceiver to the main cable should be kept as short as
possible.
Built-In Driver Overload Protection
As stated previously, the RS-485 spec requires that drivers
survive worst case bus contentions undamaged. The
ISL43485 meets this requirement via driver output short
circuit current limits, and on-chip thermal shutdown circuitry.
The driver output stages incorporate short circuit current
limiting circuitry which ensures that the output current never
exceeds the RS-485 spec, even at the common mode
voltage range extremes. Additionally, it utilizes a foldback
circuit which reduces the short circuit current, and thus the
power dissipation, whenever the contending voltage
exceeds either supply.
In the event of a major short circuit condition, this device
also includes a thermal shutdown feature that disables the
drivers whenever the die temperature becomes excessive.
This eliminates the power dissipation, allowing the die to
cool. The drivers automatically reenable after the die
temperature drops about 15 degrees. If the contention
persists, the thermal shutdown/reenable cycle repeats until
the fault is cleared. Receivers stay operational during
thermal shutdown.
Low Power Shutdown Mode
This BiCMOS transceiver uses a fraction of the power
required by its bipolar counterparts, nevertheless, the
ISL43485 includes a shutdown feature that reduces the
already low quiescent I
CC
to a 15nA trickle. They enter
shutdown whenever the receiver and driver are
simultaneously
disabled (RE = V
CC
and DE = GND) for a
period of at least 300ns. Disabling both the driver and the
receiver for less than 80ns guarantees that shutdown is not
entered.
Note that receiver and driver enable times increase when
these devices enable from shutdown. Refer to Notes 5-9, at
the end of the Electrical Specification table, for more
information.
ISL43485
相关PDF资料 |
PDF描述 |
|---|---|
| ISL43681 | Low-Voltage, Single and Dual Supply, 8 to 1 Multiplexer and Differential 4 to 1 Multiplexer |
| ISL43741IR | Low-Voltage, Single and Dual Supply, 8 to 1 Multiplexer and Differential 4 to 1 Multiplexer |
| ISL43681IR | Low-Voltage, Single and Dual Supply, 8 to 1 Multiplexer and Differential 4 to 1 Multiplexer |
| ISL43741 | Low-Voltage, Single and Dual Supply, 8 to 1 Multiplexer and Differential 4 to 1 Multiplexer |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL43485IBZ | 功能描述:RS-422/RS-485 接口 IC HI SPD 8LD -40+85 3V RS-485 TRANS 1T RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube |
| ISL43485IBZ | 制造商:Intersil Corporation 功能描述:IC TRANSCEIVER HALF DUP |
| ISL43485IBZ-T | 功能描述:IC TXRX 1TX/1RX 3V RS-485 8-SOIC RoHS:是 类别:集成电路 (IC) >> 接口 - 驱动器，接收器，收发器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 类型:发射器 驱动器/接收器数:4/0 规程:RS422，RS485 电源电压:4.75 V ~ 5.25 V 安装类型:表面贴装 封装/外壳:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SOIC 包装:带卷 (TR) |
| ISL43640 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Low-Voltage, Single Supply, 4 to 1 Multiplexer, High Performance Analog Switch |
| ISL43640_06 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Low-Voltage, Single Supply, 4 to 1 Multiplexer, High Performance Analog Switch |
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